Integer type fixes (#145)

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## Description
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Improve integer type under certain conditions.

## Motivation and Context
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issue here -->
When running the flags `-Wall -Wextra`.

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## Types of changes
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- [x] Improvement (non-breaking change that adds a new feature)
- [ ] Bug fix (fixes an issue)
- [ ] Breaking change (breaking change)
- [ ] Documentation Improvement
- [ ] Config and build (change in the configuration and build system,
has no impact on code or features)

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- [ ] My code follows the code style of this project.
- [ ] My change requires a change to the documentation.
- [ ] I have updated the documentation accordingly.
- [ ] I have added tests to cover my changes.
- [ ] All new and existing tests passed.

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Signed-off-by: GITHUB_USER <GITHUB_USER_EMAIL>


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Bug Fixes**
- Improved handling of loop variables to prevent negative overflow in
various functions, enhancing stability and reliability when processing
larger values.
  
- **Refactor**
- Updated loop variable types to `unsigned int` for better performance
and accuracy in ROM data handling across multiple components.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

src/boot/boot.c

@@ -95,7 +95,7 @@ void boot (boot_params_t *params) {
     io32_t *reboot_dst = SP_MEM->IMEM;
     size_t reboot_instructions = (size_t) (&reboot_size) / sizeof(uint32_t);
 
-    for (int i = 0; i < reboot_instructions; i++) {
+    for (unsigned int i = 0; i < reboot_instructions; i++) {
         cpu_io_write(&reboot_dst[i], reboot_src[i]);
     }
 

src/flashcart/64drive/64drive.c

@@ -99,7 +99,7 @@ static flashcart_err_t d64_load_rom (char *rom_path, flashcart_progress_callback
     size_t sdram_size = MiB(64);
 
     size_t chunk_size = KiB(128);
-    for (int offset = 0; offset < sdram_size; offset += chunk_size) {
+    for (unsigned int offset = 0; offset < sdram_size; offset += chunk_size) {
         size_t block_size = MIN(sdram_size - offset, chunk_size);
         if (f_read(&fil, (void *) (ROM_ADDRESS + offset), block_size, &br) != FR_OK) {
             f_close(&fil);

src/flashcart/sc64/sc64.c

@@ -232,7 +232,7 @@ static flashcart_err_t sc64_init (void) {
         { CFG_ID_ROM_EXTENDED_ENABLE, false },
     };
 
-    for (int i = 0; i < sizeof(default_config) / sizeof(default_config[0]); i++) {
+    for (unsigned int i = 0; i < sizeof(default_config) / sizeof(default_config[0]); i++) {
         if (sc64_ll_set_config(default_config[i].id, default_config[i].value) != SC64_OK) {
             return FLASHCART_ERR_INT;
         }
@@ -283,7 +283,7 @@ static flashcart_err_t sc64_load_rom (char *rom_path, flashcart_progress_callbac
     size_t extended_size = extended_enabled ? rom_size - MiB(64) : 0;
 
     size_t chunk_size = KiB(128);
-    for (int offset = 0; offset < sdram_size; offset += chunk_size) {
+    for (unsigned int offset = 0; offset < sdram_size; offset += chunk_size) {
         size_t block_size = MIN(sdram_size - offset, chunk_size);
         if (f_read(&fil, (void *) (ROM_ADDRESS + offset), block_size, &br) != FR_OK) {
             f_close(&fil);
@@ -445,7 +445,7 @@ static flashcart_err_t sc64_load_64dd_ipl (char *ipl_path, flashcart_progress_ca
     }
 
     size_t chunk_size = KiB(128);
-    for (int offset = 0; offset < ipl_size; offset += chunk_size) {
+    for (unsigned int offset = 0; offset < ipl_size; offset += chunk_size) {
         size_t block_size = MIN(ipl_size - offset, chunk_size);
         if (f_read(&fil, (void *) (IPL_ADDRESS + offset), block_size, &br) != FR_OK) {
             f_close(&fil);
@@ -499,7 +499,7 @@ static flashcart_err_t sc64_load_64dd_disk (char *disk_path, flashcart_disk_para
         { CFG_ID_BUTTON_MODE, BUTTON_MODE_DD_DISK_SWAP },
     };
 
-    for (int i = 0; i < sizeof(config) / sizeof(config[0]); i++) {
+    for (unsigned int i = 0; i < sizeof(config) / sizeof(config[0]); i++) {
         if (sc64_ll_set_config(config[i].id, config[i].value) != SC64_OK) {
             return FLASHCART_ERR_INT;
         }